package com.smart.wechat.login.config;

import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

@Component
public class WechatSignatureUtil {

    /**
     * 开发者ID
     */
    private static String APPID;
    @Value("${wx.oauth.appid}")
    public void setAPPID(String appid) {
        WechatSignatureUtil.APPID = appid;
    }
    /**
     * 开发者秘钥
     */
    private static String SECRET;
    @Value("${wx.oauth.appsecret}")
    public void setAPPSECRET(String secret) {
        WechatSignatureUtil.SECRET = secret;
    }

    /**
     * 授权码发放类型
     */
    private static final String GRANT_TYPE = "client_credential";
    /**
     * 授权码类型
     */
    private static final String TYPE = "jsapi";
    /**
     * 获取微信 TOKEN 接口
     */
    private static final String ACCESS_TOKEN_URL = "https://api.weixin.qq.com/cgi-bin/token";
    /**
     * 获取微信令牌接口
     */
    private static final String TICKET_URL = "https://api.weixin.qq.com/cgi-bin/ticket/getticket";
    /**
     * 请求参数名
     */
    private static final String ACCESS_TOKEN_KEY = "access_token";
    private static final String TICKET_KEY = "ticket";

    /**
     * JSON 解析
     */
    private static JsonParser parse = new JsonParser();

    /**
     * 获取签名
     * 注意 URL 一定要动态获取，不能 hardcode
     * @param url
     * @return
     */
    public static Map<String, String> getWechatSignature(String url) {
        // 获取token
        String token = getToken();
        // 获取ticket
        String ticket = getTicket(token);
        // 随机字符串
        String nonceStr = UUID.randomUUID().toString();
        // 时间戳
        String timestamp = Long.toString(System.currentTimeMillis() / 1000);
        //注意这里参数名必须全部小写，且必须有序
        String context = "jsapi_ticket=" + ticket + "&noncestr=" + nonceStr + "&timestamp=" + timestamp + "&url=" + url;
        System.out.println("============= 获取签名result ============= ：context：" + context);
        //加密
        String signature = SHA1(context);
        System.out.println("============= 获取签名result ============= ：signature：" + signature);
        //封装
        Map<String, String> result = new HashMap<String, String>();
        result.put("url", url);
        result.put("jsapi_ticket", ticket);
        result.put("nonceStr", nonceStr);
        result.put("timestamp", timestamp);
        result.put("signature", signature);
        result.put("appId", APPID);
        System.out.println("============= 获取签名result ============= ：" + result.toString());
        return result;
    }

    /**
     * 获取 token
     * @return
     */
    public static String getToken() {
        // https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=&secret=xxxxxxxxx
        String url = ACCESS_TOKEN_URL + "?grant_type=" + GRANT_TYPE + "&appid=" + APPID + "&secret=" + SECRET;
        System.out.println("============= 获取 token ============= ：url：" + url);
        //请求链接获取token
        String response = httpGetForJson(url);
        System.out.println("============= 获取 token ============= ：response：" + response);
        return ((JsonObject) parse.parse(response)).get(ACCESS_TOKEN_KEY).getAsString();
    }

    /**
     * 获取 ticket
     * @param token
     * @return
     */
    public static String getTicket(String token) {
        // https://api.weixin.qq.com/cgi-bin/ticket/getticket?access_token=xxxx&type=jsapi
        String url = TICKET_URL + "?access_token=" + token + "&type=" + TYPE;
        System.out.println("============= 获取 ticket ============= ：url：" + url);
        //请求链接获取token
        String response = httpGetForJson(url);
        System.out.println("============= 获取 ticket ============= ：response：" + response);
        return ((JsonObject) parse.parse(response)).get(TICKET_KEY).getAsString();
    }

    /**
     * SHA1加密
     * @param value
     * @return
     */
    public static String SHA1(final String value) {
        MessageDigest digest;
        try {
            digest = MessageDigest.getInstance("SHA-1");
            digest.update(value.getBytes());
            byte messageDigest[] = digest.digest();
            StringBuffer hexString = new StringBuffer();
            for (int i = 0; i < messageDigest.length; i++) {
                String shaHex = Integer.toHexString(messageDigest[i] & 0xFF);
                if (shaHex.length() < 2) {
                    hexString.append(0);
                }
                hexString.append(shaHex);
            }
            return hexString.toString();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return "";
    }


    /**
     * 发送请求
     * @param url
     * @return
     */
    public static String httpGetForJson(String url) {
        CloseableHttpClient httpclient = HttpClients.createDefault();
        try {
            // 创建 HTTPGET
            HttpGet httpget = new HttpGet(url);
            // 发送 GET 请求
            CloseableHttpResponse response = httpclient.execute(httpget);
            HttpEntity entity = response.getEntity();
            return entity == null ? "" : EntityUtils.toString(entity);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                httpclient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return "";
    }

}
